B Faraday Cage and a high voltage discharge arc

I understand how the Faraday Cage works, but what has me confused is the arching. If charge is building up on the sphere and then arching over to the cage, where then is that charge sunk to? You would think it would stop arching when there was sufficient charge on the isolated cage, no?

If the sphere keeps discharging then there must be current leaking somewhere. You can get fine corona on corners which you may not actually see except in a darkened room. Or, of course, there could be a resistive path through the support of the faraday cage.